I love Simcity. It's like programming, but substantially easier and more rewarding in the short-term. Maxis has produced some great versions of the game over the last 30 years, and Simcity 2013 is almost no exception. Unfortunately it's let down by the bugs.
This screenshot shows a theoretically impossible situation: two oil mines with full storage and two fuel production lines at the oil refinery in dire need of oil. This situation persisted for a Sim month. The two sites were properly connected. All local trade depots were capable of exporting all the affected resources and all were empty. This came about after I upgraded the density of the road outside the depot.